Dual Port PCI Express RS-232 DB9 Serial Port Card
4.5Editor score
ASIX AX99100 chip
256-byte FIFO buffer
Windows and Linux support
In this guide
Adding legacy serial connectivity to modern computers often requires a dedicated expansion card. A good PCIe serial port card ensures reliable data transmission for industrial equipment and legacy systems.
We evaluated ten top models based on chipset performance, driver support, bracket options, and overall reliability. This list covers single and dual port options for various desktop configurations.
Each pick highlights key specifications and ideal use cases to help you choose the right adapter. Please note that pricing and availability may change frequently on retail platforms.
Top 3 Picks for Best Pcie Serial Port Card
StarTech 2-Port PCI Express RS232 Serial Adapter Card
4.9Editor score
921.6Kbps speeds
Configurable power options
Low and full profile brackets
StarTech 1-Port PCI Express RS232 Serial Adapter Card
4.2Editor score
TAA compliant design
Up to 2A power
Bi-directional data speeds
Top 10 Best Pcie Serial Port Card in 2026 Compared
The following table provides a side-by-side comparison of all ten selected products to help you quickly identify the best fit for your specific system requirements.
ProductsSpecificationsEditor scorePrice
Best Budget
PCIE-SE2 2-Port PCI Express RS-232 DB9 Serial Port Card
ASIX AX99100 chipset
2 ports RS232
Windows XP to 11
Linux kernel support
4.5Editor score
Editor's Choice
StarTech 1-Port PCI Express RS232 Serial Adapter Card
16950 UART base
1 port DB9
Configurable power pin
Low profile included
4.2Editor score
Best Budget
Dual Port PCI Express RS-232 DB9 Serial Port Card
ASIX AX99100 chipset
2 independent ports
256-byte FIFO depth
Full low brackets
4.5Editor score
StarTech 2-Port PCI Express RS232 Serial Adapter Card
16950 UART base
2 ports DB9
921.6Kbps speed
TAA compliant
4.9Editor score
StarTech 2-Port PCI Express Serial Card
PCI Express 1.0a
460Kbps transfer
IRQ sharing support
Standard low bracket
4.2Editor score
PCIe Combo Serial Parallel Expansion Card
WCH382 chip
IEEE 1284 parallel
Up to 1.5Mbps
Plug and play
4.3Editor score
2-Port PCIe RS-232 DB9 Serial Port Card
ASIX AX99100
2 RS232 ports
Wide OS support
Slim PC brackets
3.7Editor score
VANTEC 2-Port Serial RS-232 PCIE Host Card
2 port serial
RS-232 standard
PCIE host
Simple installation
5.0Editor score
2-Port PCIe Serial Expansion Card with Industrial DB9
16C550 UART
WCH382 chip
230400Bps rate
Low bracket included
4.2Editor score
Single Port PCI Express x1 RS232 Serial Adapter Card
MCS9922 chipset
250Kbps data
Single lane x1
Low profile form
4.3Editor score
1. StarTech 2-Port – Best Overall Pcie Serial Port Card
StarTech 2-Port PCI Express RS232 Serial Adapter Card
ASIX AX99100 chipset
921.6Kbps max speed
256 byte FIFO buffer
Configurable power per port
This StarTech model stands out as the premier choice for demanding industrial environments. With a 4.9 rating, it offers robust connectivity for critical infrastructure and legacy systems.
Pros
- Exceptional build quality
- High data transfer rates
- Flexible power configuration
- Includes both brackets
- TAA compliance for gov
Cons
- Higher price point
- Driver installation required
We may earn a commission when you buy through this link, at no additional cost to you.
The ASIX AX99100 chipset ensures reliable communication with 256-byte FIFO buffers preventing data loss. Speeds up to 921.6Kbps make it suitable for high throughput applications.
While the cost is higher than budget options, the TAA compliance and configurable power pins justify the investment for government projects. The brackets ensure fit in any chassis.
Buyers needing reliable dual port connectivity for PLCs or medical equipment should prioritize this card. It remains the top recommendation for professional and enterprise use cases.
Enhanced Data Reliability
The deep FIFO buffer minimizes latency and prevents data packet loss during heavy transmission loads.
Configurable Power Output
Each port can supply specific voltages allowing direct connection to powered serial devices without adapters.
We may earn a commission when you buy through this link, at no additional cost to you.
2. Dual Port PCI Express – Best Budget Pcie Serial Port Card
Dual Port PCI Express RS-232 DB9 Serial Port Card
ASIX AX99100 chipset
2 independent RS232 ports
Supports Linux kernels
Includes low profile bracket
This card offers an impressive balance of cost and functionality for budget-conscious buyers. It delivers standard RS232 connectivity without compromising on core performance features.
Pros
- Very affordable pricing
- Solid chipset performance
- Compatible with Linux
- Dual port configuration
- Easy physical installation
Cons
- Driver manual for Linux
- Basic plastic housing
We may earn a commission when you buy through this link, at no additional cost to you.
Powered by the ASIX AX99100 it supports both Windows and Linux systems effectively. The dual port design allows connection to multiple legacy devices simultaneously.
Linux users will need to compile source code from the driver CD which adds some complexity. However the price point makes this a minor trade-off for most users.
Ideal for home labs or small offices needing basic serial access this card provides excellent value. It handles standard data transfer tasks reliably over time.
Universal Operating System Support
Broad compatibility ensures the card works across older Windows versions and modern Linux distributions alike.
Efficient Space Design
The included low profile bracket ensures it fits into smaller server cases without blocking other components.
We may earn a commission when you buy through this link, at no additional cost to you.
3. StarTech 1-Port – Best Premium Pcie Serial Port Card
StarTech 1-Port PCI Express RS232 Serial Adapter Card
16950 UART base
1 DB9 serial port
2A total power support
Low profile included
This single port card is engineered for scenarios where power delivery and compliance are critical. It is a top choice for procurement in regulated industries.
Pros
- Strong manufacturer reputation
- High current power pin
- TAA compliant design
- Reliable data handling
- Durable construction
Cons
- Single port limitation
- Premium pricing tier
We may earn a commission when you buy through this link, at no additional cost to you.
The ability to provide up to 2A of power through pin 9 makes it unique. This allows driving specialized equipment directly from the card.
While single port limits scalability the build quality and support are exceptional. Users needing TAA compliance for federal contracts will find it essential.
Buyers requiring high reliability for scientific sensors or medical devices should consider this model. Its premium features justify the cost in professional settings.
Powerful Pin 9 Configuration
The optional configurable power allows the card to supply up to 2A for external device needs.
Regulatory Compliance
TAA status ensures the product meets specific sourcing requirements for government and enterprise procurement.
We may earn a commission when you buy through this link, at no additional cost to you.
4. PCIE-SE2 2-Port – Reliable Industrial Pcie Serial Port Card
PCIE-SE2 2-Port PCI Express RS-232 DB9 Serial Port Card
ASIX AX99100 chipset
Full and low brackets
Windows and Linux drivers
FIFO depth transmit
This adapter delivers consistent performance for desktop and industrial devices. It supports a wide range of operating systems ensuring flexibility for different environments.
Pros
- Versatile bracket options
- Strong chipset choice
- Broad OS compatibility
- Clear installation notes
- Good for industrial use
Cons
- Driver CD required
- Slim PC manual change
We may earn a commission when you buy through this link, at no additional cost to you.
The ASIX AX99100 solution includes a 256-byte depth FIFO which reduces data loss risks. It works well with various hardware platforms including Intel and AMD.
Installation notes mention the need to manually swap brackets for slim PCs which adds a small step. The driver installation is straightforward on standard desktop setups.
Recommended for users upgrading legacy machines with POS systems or security sensors. It offers stable connectivity for critical industrial testing and control devices.
Bracket Flexibility
The card includes both full-size and low-profile brackets to accommodate standard and slim PC cases easily.
Multi-Platform Drivers
Drivers are available for almost all modern Windows versions ensuring ease of deployment across workstations.
We may earn a commission when you buy through this link, at no additional cost to you.
5. StarTech 2-Port – TAA Compliant Pcie Serial Port Card
StarTech 2-Port PCI Express Serial Card
PCI Express 1.0a
460Kbps rates
IRQ sharing support
Standard and low brackets
This card meets industry standards for PCI Express compliance and government procurement requirements. It is a solid choice for security and manufacturing equipment upgrades.
Pros
- TAA compliant for gov
- High compatibility range
- Plug and play ready
- Standard installation easy
- Durable StarTech quality
Cons
- Lower speed than others
- Older interface spec
We may earn a commission when you buy through this link, at no additional cost to you.
Data transfer rates up to 460Kbps ensure reliable communication for slower legacy devices. IRQ sharing simplifies system configuration and reduces conflicts.
While speeds are lower than newer models the stability is adequate for many industrial tasks. The standard bracket is pre-installed making initial setup straightforward.
Suitable for security devices and POS equipment where compliance is a priority. Users needing a trusted brand for government projects will find it useful.
Industry Standard Compliance
The card complies with PCI Express 1.0a ensuring broad compatibility across various motherboard generations.
Simplified Setup
Plug and play features automatically select IRQ and IO addresses reducing manual configuration effort.
We may earn a commission when you buy through this link, at no additional cost to you.
6. PCIe Combo Serial Parallel – Versatile I/O Pcie Serial Port Card
PCIe Combo Serial Parallel Expansion Card
WCH382 chipset
IEEE 1284 parallel
1.5Mbps parallel rate
Windows Linux support
This expansion card adds both serial and parallel connectivity making it ideal for older peripherals. It supports IEEE 1284 standards for high speed parallel printing.
Pros
- Dual serial and parallel
- Fast parallel rates
- Multiple OS support
- Low bracket included
- Good for legacy printers
Cons
- Driver CD manual install
- Complex setup file
We may earn a commission when you buy through this link, at no additional cost to you.
Data rates up to 1.5Mbps for parallel ports allow fast communication with legacy printers. It also provides a standard RS232 port for other industrial devices.
Users must manually install the CH38XDRV file from the CD which adds a step. However the driver ensures full functionality on modern Windows systems.
Best for users needing to connect parallel scanners or older printers alongside serial sensors. It consolidates legacy ports into one convenient PCIe slot.
Parallel Port Speed
The IEEE 1284 compliant controller supports data rates up to 1.5Mbps for efficient legacy printer use.
Dual Port Utility
Having both serial and parallel ports saves space and reduces the need for multiple expansion cards.
We may earn a commission when you buy through this link, at no additional cost to you.
7. 2-Port PCIe RS-232 – Fast Data Pcie Serial Port Card
2-Port PCIe RS-232 DB9 Serial Port Card
ASIX AX99100 chip
Standard and low brackets
Fast data transfer
Multi-platform support
This card focuses on fast data transmission for industrial and security systems. It comes with multiple brackets to fit various PC form factors effectively.
Pros
- Fast data rates
- Multiple bracket options
- Linux compatibility
- Low profile for slim
- Good value price
Cons
- Lower rating score
- Driver installation needed
We may earn a commission when you buy through this link, at no additional cost to you.
Using the ASIX AX99100 chip it ensures stable serial data transmission performance. Linux and Windows drivers are available for broad system coverage.
While user ratings are slightly lower it remains a strong performer for general serial tasks. It offers two low profile brackets which is rare for this type.
Recommended for logistics equipment and scanners needing reliable connections. Buyers with slim PCs will appreciate the extra bracket options included with the package.
Slim PC Compatibility
The inclusion of two low profile brackets ensures the card fits perfectly into small form factor chassis.
Stable Transmission
The chipset supports deep FIFO transmission preventing data loss during high volume transfers.
We may earn a commission when you buy through this link, at no additional cost to you.
8. VANTEC 2-Port – Simple Pcie Serial Port Card
VANTEC 2-Port Serial RS-232 PCIE Host Card
2 port serial design
RS-232 standard
Simple installation
Host controller card
This VANTEC model has earned a perfect user rating for its straightforward functionality. It provides dual serial ports without unnecessary complexity for basic needs.
Pros
- Perfect user rating
- Simple setup process
- Standard serial ports
- Reliable brand
- Dual port utility
Cons
- Limited product details
- Fewer advanced features
We may earn a commission when you buy through this link, at no additional cost to you.
The host card design focuses on simplicity and reliability for industrial and desktop use. It connects directly to PCIe slots for seamless integration.
While detailed specs are limited users appreciate the ease of setup. It works well for scanners and printers that need standard serial connectivity.
Buyers looking for a no-fuss dual port solution should consider this card. Its high rating suggests consistent performance and customer satisfaction over time.
Perfect User Rating
A perfect user score indicates high satisfaction with the card reliability and ease of setup.
Dual Port Utility
Two serial ports allow connection to multiple legacy devices simultaneously on a single slot.
We may earn a commission when you buy through this link, at no additional cost to you.
9. 2-Port PCIe Serial – Industrial DB9 Pcie Serial Port Card
2-Port PCIe Serial Expansion Card with Industrial DB9
16C550 UART
WCH382 chip
230400Bps rate
Low bracket included
This card uses 16C550 UART ports for fast data rates suitable for industrial control. The WCH382 chip ensures compatibility with most modern operating systems.
Pros
- Fast UART speeds
- Low profile bracket
- Windows and Linux
- Industrial grade ports
- Plug and play
Cons
- Driver CD required
- Manual setup notes
We may earn a commission when you buy through this link, at no additional cost to you.
It includes a low bracket for slim PCs and supports Linux kernels effectively. Users must install drivers from the CD file manually which is standard practice.
Data rates up to 230400Bps make it efficient for high speed serial communication. The IRQ sharing feature simplifies system resource management.
Ideal for industrial equipment and control systems needing reliable fast ports. It offers a balance of performance and compatibility for professional environments.
High Speed UART
The 16C550 UART chip supports data transfer rates up to 230400Bps for efficient communication.
OS Versatility
Compatibility extends across Windows versions and Linux kernels ensuring broad deployment options.
We may earn a commission when you buy through this link, at no additional cost to you.
10. Single Port PCI Express – Compact Pcie Serial Port Card
Single Port PCI Express x1 RS232 Serial Adapter Card
MCS9922 chipset
250Kbps data
Low profile form
PCI Express 1.0a
This single port card is designed for compact systems requiring minimal space. It uses the MCS9922 chipset for stable serial host control functionality.
Pros
- Compact low profile
- Reliable chipset
- Fast data rates
- Hardware flow control
- PCI compliant
Cons
- Single port only
- Basic interface features
We may earn a commission when you buy through this link, at no additional cost to you.
Data rates up to 250Kbps support hardware and software flow control effectively. The low profile form factor fits easily into tight server chassis.
While it offers only one port it is efficient for simple serial needs. The compliance with PCI Express 1.0a ensures broad motherboard compatibility.
Buyers needing a simple single port connection should check this model. It is a reliable choice for systems where space is a critical constraint.
Compact Form Factor
The low profile design ensures the card fits into smaller cases without obstructing other components.
Reliable Chipset
The MCS9922 chipset provides robust control for serial data transmission in industrial and desktop settings.
We may earn a commission when you buy through this link, at no additional cost to you.
Buying Guide – How to Choose the Best Pcie Serial Port Card
Selecting the right PCIe serial port card depends on your specific hardware and software requirements. This guide outlines key factors to consider before purchasing.
Number of Ports Needed
Determine how many serial devices you need to connect simultaneously. Single port cards save space while dual port cards offer more flexibility for multiple connections.
Choose a card with enough ports to avoid buying multiple adapters later.
Chipset and Performance
Look for cards using ASIX AX99100 or similar reliable chipsets. These offer deep FIFO buffers which prevent data loss during high speed transmissions.
Prioritize chipsets that match your data rate needs for industrial equipment.
Operating System Compatibility
Check if the card provides drivers for your specific Windows or Linux version. Some models require manual compilation for Linux kernels which can be complex.
Ensure driver support exists for your current OS to avoid installation issues.
Bracket Type and Fit
Standard desktop cases use full profile brackets while small form factor PCs need low profile ones. Verify the included brackets match your system chassis.
Select a card that includes both options for future upgrade flexibility.
Power Requirements
Some industrial devices require power from the serial port pins like pin 9. Ensure the card supports configurable power if you need to power external devices.
Check voltage requirements and power pins before connecting sensitive hardware.
Compliance and Certification
Government and enterprise contracts often require TAA compliance or specific standards. Verify certifications if you are working in regulated industries.
Look for TAA labels on the packaging to ensure procurement eligibility.
Brand Reputation and Warranty
Established brands like StarTech offer better customer support and warranties. Budget options may lack comprehensive support channels if issues arise.
Read reviews and check warranty terms to protect your investment effectively.
How to Use and Care for Your Pcie Serial Port Card
Before installation power down your computer and disconnect all cables. Locate an empty PCIe slot on your motherboard and insert the card firmly until it clicks into place. Secure the bracket with the screw provided.
Install the drivers included on the mini CD or download them from the manufacturer website. Restart your system to allow the OS to recognize the new hardware. You can verify the ports in Device Manager under Ports.
Regularly check the physical connections on the serial ports to ensure cables are tight. Dust accumulation inside the ports can interfere with signal quality so clean them gently if needed. Avoid bending the cables excessively to prevent internal wire damage.
Frequently Asked Questions
Do I need drivers to use a PCIe serial port card?
Yes most cards require specific drivers to function correctly especially on Windows. Linux support varies and some kernels may require compiling source code from the driver CD provided with the card.
Can I use a PCIe card in a PCIe x4 slot?
Yes PCIe cards are backward compatible. A PCIe x1 card will work perfectly fine in a x4 x8 or x16 slot on your motherboard without any performance issues.
What is the maximum data transfer speed?
Speeds vary by chipset but most high quality cards support up to 921.6Kbps or 230400Bps. This is sufficient for most industrial equipment and legacy device communications.
Will this card work on Linux systems?
Many cards support Linux but you may need to compile source code for specific kernel versions. Check the product details to ensure kernel compatibility before purchasing.
How do I choose between full and low profile brackets?
Full profile brackets fit standard desktop cases while low profile ones fit slim servers. Choose based on your computer case size or select a card that includes both.
Are these cards compatible with USB to serial converters?
No PCIe cards are internal hardware while USB converters are external. PCIe cards offer better performance and reliability for heavy industrial use cases.
Final Thoughts on Choosing the Best Pcie Serial Port Card
We reviewed ten top PCIe serial port cards ranging from budget options to premium TAA compliant models. The StarTech dual port card stands out for reliability while the Dual Port PCI Express card offers excellent value.
Prioritize the chipset performance and bracket compatibility to ensure long term reliability. If you need government procurement compliance look for TAA labeled models specifically for those projects.
Always verify current pricing and stock availability on retail platforms before buying. Features and requirements may change over time so double check specifications before finalizing your purchase.